Utility of DNA-Specific Stains in Micronuclei Assay as a Marker of Genotoxicity in Oral Potentially Malignant Disorders and Oral Squamous Cell Carcinoma.

Abstract

Background:The term oral potentially malignant disorder (OPMD) was recommended to refer to precancer as it conveys that not all disorders described under this term may transform into cancer. Oral squamous cell carcinoma (OSCC) arises through an accumulation of genetic alterations, deoxy ribonucleic acid (DNA) changes, and epigenetic alterations. Thus, a simple yet a sensitive and specific test for early diagnosis is the need of an hour. The micronuclei (MN) assay in exfoliated epithelial cells is potentially an excellent biomarker to detect chromosome loss or malfunction of mitotic spindle.Aim of the Study:To compare the frequency of MN in exfoliated cells from oral mucosa exposed to genotoxic agents using different staining procedures and to observe the incidence of micronucleus in potentially malignant and malignant lesions.Materials and Methods:The study was undertaken to observe the cytogenetic damage in the exfoliated buccal cells of 75 cases of tobacco-related PMDs, OSCC and control subjects (25 cases from each group) and were evaluated with nonspecific May-Grünwald Giemsa stain and DNA-specific Feulgen stain. The results were statistically determined using SPSS version 17.0.Results:Correlation analyses in the present study depicted that MN frequency was significantly more in oral squamous cell carcinoma than OPMDs and normal group (P < 0.05). Giemsa-stained slides correlated significantly with karyorrhexis, karyolysis, condensed chromatin, and binucleates, whereas no such correlations were found with DNA-specific stains.Conclusion:Malignant transformation is accompanied by loss of cell capacity to evolve to death in situations of DNA damage. These findings indicate that nuclear anomalies may be misinterpreted as MN with nonspecific DNA stains and lead to false-positive results in studies with cells of epithelial origin.